Initial commit: Kottgard production website code

src/domain/services/CartDomainService.ts

@@ -0,0 +1,48 @@
+import { CartItem, Product, ProductCustomization } from '@/domain/entities';
+import { CustomizationDomainService } from './CustomizationDomainService';
+
+/**
+ * DOMAIN SERVICE — Cart business rules (pure functions, no storage)
+ */
+export class CartDomainService {
+  static calculateSubtotal(items: CartItem[]): number {
+    return items.reduce((sum, item) => sum + item.product.price * item.quantity, 0);
+  }
+
+  static calculateItemCount(items: CartItem[]): number {
+    return items.reduce((sum, item) => sum + item.quantity, 0);
+  }
+
+  static addItem(
+    items: CartItem[],
+    product: Product,
+    customization: ProductCustomization,
+    customizationLabel: string,
+    quantity = 1
+  ): CartItem[] {
+    const id = CustomizationDomainService.getCartItemKey(product.id, customization);
+    const existing = items.find((item) => item.id === id);
+
+    if (existing) {
+      return items.map((item) =>
+        item.id === id ? { ...item, quantity: item.quantity + quantity } : item
+      );
+    }
+
+    return [
+      ...items,
+      { id, product, quantity, customization, customizationLabel },
+    ];
+  }
+
+  static removeItem(items: CartItem[], id: string): CartItem[] {
+    return items.filter((item) => item.id !== id);
+  }
+
+  static updateQuantity(items: CartItem[], id: string, quantity: number): CartItem[] {
+    if (quantity <= 0) {
+      return CartDomainService.removeItem(items, id);
+    }
+    return items.map((item) => (item.id === id ? { ...item, quantity } : item));
+  }
+}